Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines of this kind generally comprise a tower and a rotor arranged on the tower. The rotor, which typically comprises a hub and a plurality of blades, is set into rotation under the influence of the wind on the blades. Said rotation generates a torque that is normally transmitted through a rotor shaft to a generator, either directly or through the use of a gearbox. This way, the generator produces electricity which can be supplied to the electrical grid.
During installation, one or more blades are to be mounted to the wind turbine hub. The hub comprises a plurality of annular mounting flanges with openings. The blade comprises a plurality of fasteners, such as bolts, or pins or studs at its blade root. During installation, these fasteners are to be fitted into the openings in the mounting flanges.
The installation of wind turbine blades has become more and more of a challenging task due to the general tendency to considerably increase the size and weight of modern wind turbines. During installation, the wind turbine blade may be hoisted towards the rotor hub. An aerodynamic force may be exerted on the wind turbine blade and may provoke sudden movements and possibly oscillations of the blade during the hoisting operation. Fitting the blade to a hub may thus be complicated and time-consuming.
Frequent difficulties may arise during the lifting operation due to oscillations. In order to perform the installation of the blade, manual aid may often be required. This can lead to an increase of the risk for the operator especially if the operator may be standing directly under or near the load.
The oscillation during hoisting operation may also lead to possible damage to the wind turbine blade or to other parts of the wind turbine. Another complicating factor may be delays during the installation process. This may lead to an increase in the cost of installation, especially in offshore installations where the use of dedicated vessels may be required. The operational cost of installation may be increased significantly.
Wind turbine farms are often situated in remote landscapes, on hill-tops or offshore locations and typically in these places the lifting of the wind turbine blade may be subjected to high winds.
In order to reduce oscillations of blades, the use of tagline systems is known, i.e. control ropes from a vessel or crane that are tied to a blade to prevent oscillations. One problem with these systems may be that they may not completely prevent movements and blade oscillations caused by the wind. A further disadvantage of these systems may be that during gusts of wind there may be a risk of the control ropes being cut on the sharp edges of the blade to be installed. A tagline or rope may also damage a blade by rubbing against it.
The examples of methods and components of the present disclosure seek to at least partially reduce one or more of the aforementioned problems.